Evolution-based medicine
One oddity in the ongoing creation/evolution debate is the failure of creationists to object to evolution-based medicine -- that is, medical practices which are premised on the existence of evolution by natural selection, and would be useless and pointless if that theory of evolution were untrue. Probably the most pronounced example of evolution-based medicine is the recurring vaccination against viruses. Some viruses, it should be noted, require only a single vaccination or infection to provide lifelong immunize the recipient. But others, most particularly the flu, require the engineering of a new vaccination each year. Now, it's important to understand just what a vaccination is, and why it works. A sample of the current version of the virus is bred for weakness in the lab, and is then stimulated to reproduce a whole bunch to fill those little vials that get sent around the world for injection into people's arms. Once injected, the virus is strong enough to provoke a reaction but too weak to do any harm. So, here there are two instances of evolution, one natural and the other directed, that make recurring vaccinations at all relevant. The first is the evolution of the virus itself. A one time lifetime vaccination would work just fine -- but for the fact that the virus mutates and the most virulent new strains will be the ones that spread to other hosts, even to hosts that have already developed immunity to earlier strains. Conversely, but for the fact that those minor mutations exist to be manipulated by man, enabling us to breed a weak version of the same virus, no vaccine could be developed. Now, the creationist retort will be that the flu virus may indeed have the power to evolve new formulas of virility, but it will only ever be a virus. However, modern medicine also relies on speciation, or rather on the results of past speciation, among higher orders of animals. Specifically, drug testing of various degrees is practiced on animals based on their genetic closeness to humans; and for the same reasons, transplants are effected of some animal parts (such as valves and ligaments) into humans. We would not test new a cancer drug first on a fish, but more likely on a mouse; but if we did not share commonalities with the mouse derived from our more recent shared ancestorship, there is no reason why the mouse should provide any better information about the drug's effect on humans. And, after the mouse, we proceed to the chimpanzee or a similar monkey. Again, what sense would that make if the mouse had been the product of one wholesale act of creation, the monkey another, and the human yet another. And yet, what cancer-stricken creationist would find fault with receiving a treatment thought to be effective based solely on its effect on other animals? Or, what creationist would accept an experimental treatment shown to be effective on lizards but not on lab rats, or even one that worked on mice but had no effect on monkeys? The conscientious stand for a dedicated and certain creationist to take would be refuse any course of medical treatment which suggested the common ancestry of humans and other species. Conversely, evolutionists could refuse to accept medical treatments which rely on the truth of creationism, but there are none. Of course, some might point to prayer and similar things like burning candles, but one can certainly believe in a God and still accept that all life on Earth is the result of a single unbroken course of evolutionary advancement.